21-10-2012, 05:51 PM
There's not much difference between a natural gravity driven collapse and a CD... in each case the structure loses aggregate strength and can't stand. The key is that failure progresses or migrates through the structure. It's not a big bang and it all falls down.
It could be a big bang which say knocks out a transfer truss and then a progression of failures ensues. That seems less likely because that would be a pretty huge blast to take out the very heavy steel in one instant. But it's possible. It's also possible that there was a slow weakening at the steel at a joint heated up. We can't know but the visual part came 8 hrs after the first explosions were reported by Jennings.
It could be a big bang which say knocks out a transfer truss and then a progression of failures ensues. That seems less likely because that would be a pretty huge blast to take out the very heavy steel in one instant. But it's possible. It's also possible that there was a slow weakening at the steel at a joint heated up. We can't know but the visual part came 8 hrs after the first explosions were reported by Jennings.